The Skin Histology and Characterization Core (SHCC) will provide SDRC investigators with services to aid them in the histopathologic and molecular characterization of skin samples derived from animal models, primarily mutant or genetically engineered mice. In addition, this core will provide sectioning and histopathological analysis of de-identified, formalin fixed, paraffin embedded dermatopathology archived samples provided by Core B. The aims of the SHCC are: 1) To provide expert service in the processing, embedding, sectioning, and staining of skin specimens from research animals, including murine embryos, and sectioning and staining of archived, de-identified human tissue; 2) To provide expert service and training in protein immunohistochemical staining using skin samples; to establish and provide advice in determining effective staining protocols for novel antibodies; 3) To provide expert service and training for RNA in situ hybridization of skin samples using radioisotopic and colorimetric methodologies; 4) To provide expert interpretation and training in the histopathological evaluation of animal and human skin histology. We will ensure accurate correlations between animal model phenotypes and human diseases. The SHCC will build upon the existing laboratory infrastructure operating in the Department of Dermatology to enhance cutaneous biology research at the University of Pennsylvania. The proposed SHCC will be a shared facility that will help investigators conduct their independently NIH funded research projects in a more time- and cost-efficient manner. The SHCC will consolidate manpower and promote cost-effectiveness by providing high quality services at a lower cost than if each investigator were to attempt to establish these analytical techniques individually. The SHCC services will help SDRC investigators characterize the phenotype of their genetically engineered mouse models at the histologic, protein, and mRNA levels, and then correlate this data with relevant human diseases. Such services are critical for generating sound scientific hypotheses linking animal models with human diseases. The SHCC will interact closely with Core B in coordinating the staining and analysis of archived dermatopathology specimens. To assure high quality service, the SHCC will establish an oversight committee. The SHCC will also interact with Core C by providing histologic, immunohistochemical, and mRNA in situ hybridization analysis of reconstituted skin and keratinocyte xenografts produced by this core. These services will attract established investigators to cutaneous biology and assist young investigators in obtaining important data for their research projects. RELEVANCE (See instructions): The Skin Histology and Characterization Core will facilitate research on cutaneous diseases by providing cost-effective, high quality services for skin tissue that include the following: processing, staining, protein immunohistochemistry, mRNA in situ hybridization, and histologic evaluation. These services will allow investigators to effectively correlate the cutaneous phenotype of an animal model with a human disease.